package com.cx.base.day13_io.io_autoTest;

import java.io.UnsupportedEncodingException;

/**
 * @Author: robert.song
 * @Date: Created in 2021/11/25
 */

public class ChangeCharset {
    /**
     * 7位ASCII字符，也叫作ISO646-US、Unicode字符集的基本拉丁块
     */
    public static final String US_ASCII = "US-ASCII";
    /**
     * ISO拉丁字母表 No.1，也叫做ISO-LATIN-1
     */
    public static final String ISO_8859_1 = "ISO-8859-1";
    /**
     * 8 位 UCS 转换格式
     */
    public static final String UTF_8 = "UTF-8";
    /**
     * 16 位 UCS 转换格式，Big Endian(最低地址存放高位字节）字节顺序
     */
    public static final String UTF_16BE = "UTF-16BE";
    /**
     * 16 位 UCS 转换格式，Litter Endian（最高地址存放地位字节）字节顺序
     */
    public static final String UTF_16LE = "UTF-16LE";
    /**
     * 16 位 UCS 转换格式，字节顺序由可选的字节顺序标记来标识
     */
    public static final String UTF_16 = "UTF-16";
    /**
     * 中文超大字符集
     **/
    public static final String GBK = "GBK";

    public static final String GB2312 = "GB2312";

    /**
     * 将字符编码转换成US-ASCII码
     */
    public String toASCII(String str) throws UnsupportedEncodingException {
        return this.changeCharset(str, US_ASCII);
    }

    /**
     * 将字符编码转换成ISO-8859-1
     */
    public String toISO_8859_1(String str) throws UnsupportedEncodingException {
        return this.changeCharset(str, ISO_8859_1);
    }

    /**
     * 将字符编码转换成UTF-8
     */
    public String toUTF_8(String str) throws UnsupportedEncodingException {
        return this.changeCharset(str, UTF_8);
    }

    /**
     * 将字符编码转换成UTF-16BE
     */
    public String toUTF_16BE(String str) throws UnsupportedEncodingException {
        return this.changeCharset(str, UTF_16BE);
    }

    /**
     * 将字符编码转换成UTF-16LE
     */
    public String toUTF_16LE(String str) throws UnsupportedEncodingException {
        return this.changeCharset(str, UTF_16LE);
    }

    /**
     * 将字符编码转换成UTF-16
     */
    public String toUTF_16(String str) throws UnsupportedEncodingException {
        return this.changeCharset(str, UTF_16);
    }

    /**
     * 将字符编码转换成GBK
     */
    public String toGBK(String str) throws UnsupportedEncodingException {
        return this.changeCharset(str, GBK);
    }

    /**
     * 将字符编码转换成GB2312
     */
    public String toGB2312(String str) throws UnsupportedEncodingException {
        return this.changeCharset(str, GB2312);
    }

    /**
     * 字符串编码转换的实现方法
     *
     * @param str        待转换的字符串
     * @param newCharset 目标编码
     */
    public String changeCharset(String str, String newCharset) throws UnsupportedEncodingException {
        if (str != null) {
            //用默认字符编码解码字符串。与系统相关，中文windows默认为GB2312
            byte[] bs = str.getBytes();
            return new String(bs, newCharset);    //用新的字符编码生成字符串
        }
        return null;
    }

    /**
     * 字符串编码转换的实现方法
     *
     * @param str        待转换的字符串
     * @param oldCharset 源字符集
     * @param newCharset 目标字符集
     */
    public String changeCharset(String str, String oldCharset, String newCharset) throws UnsupportedEncodingException {
        if (str != null) {
            //用源字符编码解码字符串
            byte[] bs = str.getBytes(oldCharset);
            return new String(bs, newCharset);
        }
        return null;
    }

    public static void main(String[] args) throws UnsupportedEncodingException {
        ChangeCharset test = new ChangeCharset();
        String str = "This is a 中文的 String!";
        System.out.println("str：" + str);
        System.out.println("strEncoding==UTF-8？" + str.equals(new String(str.getBytes(), "UTF-8")));
        String gbk = test.toGBK(str);
        System.out.println("转换成GBK码：" + gbk);
        System.out.println("strEncoding==gbk?`   " + gbk.equals(new String(str.getBytes(), "GBK")));

        String ascii = test.toASCII(str);
        System.out.println("转换成US-ASCII：" + ascii);
        System.out.println();

        String iso88591 = test.toISO_8859_1(str);
        System.out.println("转换成ISO-8859-1码：" + iso88591);
        System.out.println();

        gbk = test.changeCharset(iso88591, ISO_8859_1, GBK);
        System.out.println("再把ISO-8859-1码的字符串转换成GBK码：" + gbk);
        System.out.println();

        String utf8 = test.toUTF_8(str);
        System.out.println();
        System.out.println("转换成UTF-8码：" + utf8);
        String utf16be = test.toUTF_16BE(str);
        System.out.println("转换成UTF-16BE码：" + utf16be);
        gbk = test.changeCharset(utf16be, UTF_16BE, GBK);
        System.out.println("再把UTF-16BE编码的字符转换成GBK码：" + gbk);
        System.out.println();

        String utf16le = test.toUTF_16LE(str);
        System.out.println("转换成UTF-16LE码：" + utf16le);
        gbk = test.changeCharset(utf16le, UTF_16LE, GBK);
        System.out.println("再把UTF-16LE编码的字符串转换成GBK码：" + gbk);
        System.out.println();

        String utf16 = test.toUTF_16(str);
        System.out.println("转换成UTF-16码：" + utf16);
        String gb2312 = test.changeCharset(utf16, UTF_16, GB2312);
        System.out.println("再把UTF-16编码的字符串转换成GB2312码：" + gb2312);
    }

}
